This entry describes several enzymes that successively methylate the L-lysine9 residue of histone H3 (H3K9), ultimately generating a trimethylated form. These modifications influence the binding of chromatin-associated proteins. In general, the methylation of H3K9 leads to transcriptional repression of the affected target genes. cf. EC 126.96.36.1997, [histone H3]-lysine9 N-methyltransferase, EC 188.8.131.528, [histone H3]-lysine9 N-dimethyltransferase, and EC 184.108.40.2066, [histone H3]-N6,N6-dimethyl-lysine9 N-methyltransferase.
EC 220.127.116.115 created 1976 as EC 18.104.22.168, modified 1982, modified 1983, part transferred 2019 to EC 22.214.171.1245, modified 2020